A patentability investigation was conducted and the following U.S. Patents were discovered: U.S. Pat. No. 6,155,792 to Hartley (“Hartley”), U.S. Pat. No. 6,086,339 to Jeffrey (“Jeffrey”), U.S. Pat. No. 5,992,517 to McAnally (“McAnally”), U.S. Pat. No. 4,417,860 to Justice (“Justice”), and U.S. Pat. No. 3,397,643 to Jespen (“Jespen”).
Hartley teaches an apparatus for pumping fluids comprising a tubular housing; a pump assembly in the tubular housing; a rotating assembly in the tubular housing; a gear assembly coupled to the rotating rod assembly; and a motor assembly coupled to the tubular housing and the gear assembly. The tubular housing has at least one intake port for the inflow of fluids from the annulus. The pump assembly has a generally hollow reciprocating pump plunger with apertures. The rotating rod assembly has a rotating rod assembly and surrounds the reciprocating pump plunger. The rotating rod has a number of apertures for the inflow of fluids. Hartley also discloses the use of helical tracks with ball bearings. Additionally, Hartley discloses the use of an electric motor installed with a pressure sensor that allows the well to be placed on automatic and be pumped within certain fluid level parameters.
Jeffrey describes a pumping housing having an inlet and an outlet, a plunger reciprocally disposed in the pumping housing, a prime mover having a rotating output shaft, and a transmission connected to the plunger and the prime mover. The transmission is adapted to convert rotating motion of the output shaft of the prime mover into reciprocating motion of the plunger.
McAnally discloses a downhole reciprocating plunger pump that includes multiple cylinders with a crankshaft supported on a frame for rotation about an axis. As the crankshaft rotates about an axis, fluid flows into various chambers for discharge into an accumulator space up through a conduit to a storage tank.
Justice teaches a displacement pump with a motor, a small diameter transmission mechanism having axially aligned input and output shafts; and a pump mechanism mounted thereon. The pump has a cylinder with inlet and outlet ports, and a cam shaft connected to and driven by the output shaft of the transmission mechanism. The pump also has a piston working in the cylinder, driven by the cam shaft.
Jepsen teaches drawing well fluid into a charging chamber while simultaneously discharging a like quantity of well fluid from a pumping chamber into the well tubing during the up-stroke of the pump, then transferring the well fluid from the charging chamber to the pumping chamber against the back pressure of the well fluid in the well tubing during the down-stroke of the pump.
The foregoing prior art pumping systems, as well as other prior art, are hindered with a high cost and frequency of well servicing. Such prior art pumping system posses a lot of mechanical wear and tear, especially with the ball screw and ball screw nut.
Therefore, what is needed is a downhole pumping apparatus that does not posses the deficiencies associated with the prior art pumping systems, and one which greatly extends the useful life of the ball screw and ball screw nut.